The present invention relates to food patty-molding machines. The invention particularly relates to food patty-molding machines which incorporate a reciprocating mold plate having patty-forming cavities which are cyclically filled to form patties, and then emptied, the patties being discharged to a patty-receiving area.
Food patty-forming or molding machines are described, for example, in U.S. Pat. Nos. 3,887,964; 4,372,008 and 4,821,376. A typical food patty-forming machine or apparatus 20 is illustrated in FIG. 1. This machine is described in detail in U.S. Pat. No. 3,887,964 and has been marketed as the FORMAX 26 machine by Formax, Inc., of Mokena, Ill. Molding machine 20 includes a machine base 21 which supports the operating mechanisms of the machine and contains hydraulic actuating systems, electrical actuating systems, and most of the machine controls.
The food patty-molding machine 20 includes a supply means 24 for storing and supplying a moldable food product, such as ground beef, fish, pork, chicken, potatoes, or the like, to the processing mechanisms of the machine. Supply means 24 includes a large food product storage hopper 25 that supplies a food pump system 26. System 26 includes two alternately operating food pumps (one shown); other machines typically include only a single food pump. The two food pumps continuously pump food, under pressure, into a valve manifold connected to a cyclically operable molding station 28. Molding station 28 includes a multi-cavity mold plate 32 that moves cyclically between a fill position, shown in FIG. 1, and a discharge position in which its mold cavities are outside of station 28, aligned with a set of knock-out cups 33.
Food supply means 24 includes a conveyor belt 31 that extends completely across the bottom of hopper 25. In FIG. 1, a limited supply of food product 38 is shown in hopper 25; a much greater supply could be stored in the hopper without exceeding its capacity. The forward end of hopper 25 communicates with a vertical hopper outlet 39 that leads downwardly into two pump chambers; only one pump chamber 69 is shown. Three motors drive three vertical feed screws. Only one motor 47 and one feed screw 53 are shown in FIG. 1.
The upper part of a pump housing 71 comprises a plate 81 that supports the mold plate 32. The mold plate 32 includes a plurality of individual mold cavities 86 distributed in a single row across the width of the mold plate; mold cavities 86 are alignable with the manifold outlet fill passage 79. A mold cover 82 is disposed immediately above mold plate 32, closing off the top of each of the mold cavities 86. The mold cover 82 may include a conventional breather plate. Suitable spacers (not shown) are provided to maintain the spacing between the cover 82 and the support plate 81, essentially equal to the thickness of the mold plate 32. A housing 88 is positioned over the cover plate 82. The housing 88 encloses the operating mechanism (not shown) for the knock-out cups 33.
In the operation of the patty-molding machine 20, a supply of ground meat or other moldable food product 38 is placed into the hopper 25, and is advanced toward the hopper outlet 39 by the conveyor 31. Whenever one of the food pump plungers, such as the plunger 68, is retracted to expose a pump cavity (e.g., the cavity 69), the vertical feed screws 53 aligned with that pump cavity are actuated to feed the food product into the pump cavity.
In FIG. 1, pumping system 26 is illustrated with the mold plate 32 in its fill position, and with the pump 61 pumping the moldable food product through the manifold 27. The pump 61, as shown, has just begun its pumping stroke, and has compressed the food product in pump cavity 69, forcing it under pressure into the manifold 27. As operation of the machine 20 continues, the plunger 68 advances and food product flows into the mold cavities 126, there is a relatively constant pressure on the food product and chamber 69, manifold 27, fill passage 79, and cavities 86.
In describing the operation of molding mechanism 28, and particularly the mold plate 32, it is convenient to start with the mold plate 32 in the fill position in FIG. 1. In each molding cycle, mold plate 32 remains in this fill position for a limited dwell interval. As the mold cavities 86 move into the fill position, one of the two food pumps of machine 20 pumps food product through manifold 27 and fill passage 79, filling the mold cavities. To assure complete filling of the mold cavities, the food pump must apply a substantial pressure to the food product.
Following the fill dwell interval, mold plate 32 is moved outwardly, to the right from its fill position, as shown in FIG. 1, until it reaches a discharge position with its mold cavities 86 aligned with knock-out cups 33. As mold plate 32 moves toward its discharge position, mold cavities 86 all move clear of fill passage 79 before any part of those cavities projects out of mold station 28, beyond support plate 81 and cover 82. Thus, the food pump in machine 20, as shown in FIG. 1, remains sealed off at all times. A second dwell interval occurs at the discharge position of mold plate 32, during which knock-out cups 33 move downwardly through the mold cavities, discharging the molded food patties onto a patty-receiving area, e.g. a take off conveyor (not shown).
Following discharge of the molded food patties, mold plate 32 is moved back toward its fill position so that mold cavities 86 can again be filled with food product. Again, mold cavities 86 are completely inside molding mechanism 28, sealed off, before they come into alignment with fill passage 79.
Although a single fill passage 79 is shown in FIG. 1, it is also known to provide multiple fill orifices which together are substantially coextensive with the area of the cavities, such as described in U.S. Pat. Nos. 4,356,595; 4,821,376 and 4,372,008.
The present inventor has recognized that the throughput (quantity of patties per time period of machine operation), of food patties formed by the aforementioned food patty-forming machine is limited by the speed of the machine and the number of cavities that can be aligned across the single row. The present inventor has recognized that it would be desirable that the throughput of such a machine be increased, while maintaining a consistent quality of the patties formed by such a machine.
The invention provides a mold plate assembly for a patty-forming apparatus that includes a reciprocating mold plate having patty-forming cavities, with at least two rows of cavities aligned in a longitudinal direction. The mold plate reciprocates between a cavity fill position and a patty discharge or knock-out position. The mold plate includes a fill hole. The assembly includes a top fill plate structure and a bottom fill plate arranged facing opposite sides of the mold plate. Front and rear outlet slots are arranged through the top fill plate structure to fill food product into the mold cavities when the mold plate is in the fill position. During filling of food product into the cavities, a pressurized food product flow distribution path is established through the bottom fill plate, through the fill hole of the mold plate, through the top fill plate structure, through the outlet slots, and into the cavities. The fill hole is reciprocated between an open and a closed position with the reciprocating mold plate, to either allow food product into the mold cavities when the mold plate is in the fill position, or to prevent pressurized flow through the fill openings when the mold plate is in the closed position.
According to the invention, the rearward row of cavities is not thereby exposed to pressurized food product from front outlet slots during retraction or extension of the rearward cavities during mold plate reciprocation. Thus, the forward row of mold cavities is exposed to only the pressurized front outlet slots during the filling interval; and the rearward row of cavities is exposed to only the pressurized front outlet slots during the filling interval. In this way, the rearward row of cavities which pass by the front outlet slots is not over-filled or over-pressured by being exposed to pressurized front outlet slots before or after filling by the corresponding rear outlet slots.
According to the invention, the production of food patties by the patty-forming apparatus per operating period is effectively doubled compared to an apparatus with a single row of mold cavities. The mold plate assembly allows for the use of multiple rows of cavities in the mold plate and ensures consistent filling in both the rearward and forward rows of cavities. Each row of cavities is filled simultaneously without any row of cavities being over-filled, or over-pressured. The resultant food patties will have a consistent quality and density, and a resultant consistent cooking time.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings.